Process for refining mineral oils



Patented Sept. 25, 1934 UNITED STATES PATENT. OFFICE rnoonss ron nnrmnze MINERAL oms No Drawing. Application March 23, 1931,

. Serial No. 524,154

21 Claims. (o1. 196-24) This invention relates generally to" the purification of crude mineral oil, its distillates (obtained by distillation or cracking) and mineral oil residues, and has for its object the removal therefrom of organic sulfur compounds, elementary sulfur phenolic bodies, sulfonic acids and other acidic constituents.

For commercial reasons, my inventioncan be advantageously employed in connection with w products such as gasoline, kerosene, pressure distillate and the like, resulting from the cracking of mineral oils.

Crude mineral oil and its products are of complex constitution depending upon the source of the material and the type of treatment it undergoes. analysis of any mineral oil product. Amongst other things, these products contain phenolic bodies, hydrogen sulfide, free sulfur and organic sulfur bodies such as mercaptans, thioethers, thiophenes, sulfonic acids and disulfides.

I have discovered that anhydrous liquid ammonia or substantially anhydrous liquid ammonia can be utilized effectively in removing the aforementioned sulfur bodies and phenolic bodies from crude mineral oil and its products. Where the mineral oil material has been treated with sulfuric acid, the anhydrous liquid ammonia can be used in lieu of the sodium hydroxide commonly employed. Thus in one operation, use is made of a volatile and easily recoverable alkali which neutralizes the acidic character of the acid-treated material and which effects the removal of the aforementioned undesirable and malodorous bodies. I desire to state herein that my process is not concerned especially with the removal of hydrogen sulfide as this is easily removed by other well known processes and it is preferable to do so.

Anhydrous liquid ammonia dissolves free sulfur, phenolic bodies, many. organic acids and mereaptans very readily. Other organic sulfur compounds such as thiophenes and thioethers do not dissolve very readily but distribute themselves between the mineral oil and the liquid ammonia. The greatest difficulty is experienced with the removal of organic disulfides as these compounds have an unfavorable distribution ratio. I have discovered that if the disulfide content of mineral oils is converted to mercaptans by reduction, substantially complete removal of the-aforementioned undesirable and malodorous bodies is easily effected by treatment with anhydrous liquid ammonia. The reducing action may take lid.

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place prior to and independently of the ammonia As a. result, one cannot predict the truetreatment or the reducing agent may be contained in the liquid ammonia. Some reducing agents, soluble in anhydrous liquid ammonia, which are particularly eifective in reducing the disulfide content of mineral oils are ammonium sulfide, sodium sulfide, potassium sulfide, ammono-sulfurous acid, sulfur, cyanides, hydroxylamine, hydrazine and the like. For example, ammonium sulfide dissolved in liquid ammonia reacts with disulfides to form mercaptans and free sulfur and these are then readily extracted by the liquid ammonia.

' The reaction of the sulfur bodies with reducing agents is greatly facilitated by adding to the liquid ammonia, substances which have the nature of amides soluble in anhydrous liquid ammonia-such as sodium amide, potassium amide and the like. In other cases, the reaction is facilitated by adding to the anhydrous liquid ammonia, ammonium salts soluble in liquid am- 7 monia but not possessing oxidizing propertiessuch as ammonium chloride, ammonium acetate, ammonium nitrate and the like.

The extraction of the sulfur content from the oil may also be facilitated by adding to or dissolving in the liquid ammonia, substances which will react with the organic sulfur bodies so as to remove the sulfur therefrom, forming therewith compounds readily soluble in liquid ammonia. Sodium cyanide, potassium cyanide and'ammonium cyanide are examples of such compounds which react with certain sulfur bodies to form thiocyanates, which are readily soluble in liquid ammonia.

If desired, the various facilitating agents may 0 be added to the oil prior to and independently of the liquid ammonia treatment.

Whether a body or compound is suspended or dissolved in anhydrous liquid ammonia, is a matter not of practical importance and when'it is 5 stated that a body is dissolved it is meant to likewise convey suspension of particles approaching molecular dimensions.

Contrary to most beliefs and statements by prior inventors, anhydrous liquid ammonia is sub- 0 stantially immiscible with mineral oil.. Consequently, mineral oil material contacted or agitated with anhydrous liquid ammonia eventually resolves itself; and one obtains a liquid oil phase and a liquid ammonia phase, the latter being uppermost. If the contact of the two materials is brought about in the presence of one or more of the following: reducing agents, modifying agents and cyanides, substantially complete separation of the two liquids is simply and easily effected as by drawing of! the oil layer or by decanting the ammonia, layer containing the aforementioned undesirable and malodorous bodies.

In carrying out the mechanics of the process, 1 preferably run the oil product into a suitable cylinder, close oil the oil supply and introduce \mder pressurejhe desired quantity (usually a volume equal to that of the oil) of anhydrous liquid ammonia carrying in solution or suspension the chemicals necessary to effect the desired reaction, depending on the sulfur content of the oil and the nature of the sulfur bodies to be removed. The two immiscible liquids are then brought into intimate contact by any suitable agitation, or if desired, the treating liquid may be forced through the oil from beneath in a continuous stream for a time necessary to complete the reaction.

Some oils may require successive extractions or treatment separately with different chemical agents dissolved in the ammonia in order to give them the desired purity. After a test of the oil shows the sulfur and phenolic content to have been satisfactorily reduced,'the liquids are permitted to stand for a few minutes to enable the ammonia to rise and I drive the ammonia over into a condenser for further use and thus deposit its dissolved impurities in this receptacle.

- Many other variations of the mechanical handling of the process will readily suggest themselves to the industrial chemist, the chief obiective being the ridding of the ammonia of its' dissolved or suspended content, impregnating the ammonia with the desired fresh chemical agents and using it again in treatment of new batches of oil product, and of course in carrying this out on a large scale, recourse will be had to suitable countercurrent and. continuous methods of treatment of liquids under pressure, many of which are well known in v By the expression anhydrous liquid ammonia" is meant the liquid ammonia of commerce, which is substantially NH; but contains traces of moisture and other impurities.

The e ression mineral o in the claims is meant to embrace such examples as crude mineral oils, derived from any source, mineral oil fractions obtained by distillation or cracking including straight run products-and cracked distillates suchas gasoline, kerosene, illuminating oils, pressure distillate, lubricating oils and the like and mineral oilresidues available in any number of mineral oil treatments.

while I have in the foregoing described in some detail the preferred embodiment of my invention and some variants thereof, it will be understood that this is only-for the purpose of making the invention more clear and that the invention is not to be regarded as limited to the details of operation described, nor is it dependent upon the soundness or accuracy of the theories which I have advanced as to the reasons for the advantageous results attained. 0n the other hand, the invention is to be regarded as limited only by the terms ofthe accompanying claims, in which it is my intention to claim all novelty inherent therein as broadly as is possible in view of the prior art.

I claim as my invention: 4

1. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising reducing the disulfides to mercaptans with a reducing agent, extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase, allowing the oily mixture to separate into two liquid phases, and effecting the separation of the resulting essentially liquid ammonia phase predominantly composed of ammonia from the oil phase.

,2. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising first reducing the disulfides with a reducing agent, then extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase, allowing the oily mixture to separate into two liquid phases, and effecting the separation of the resulting essentially liquid ammonia phase predominantly composed of ammonia from the oil phase.

3. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising reducing the disuliides with a reducin agent while extracting the sulfur bodies and other impurities from the mineral'oii with substantially anhydrous liquid ammonia at a tempera-s ture and pressure at whichboth materials are in the liquid phase. allowing the oily mixture to separate into two phases and removing the essentially liquid ammonia phase predominantly composed of ammonia from the oil phase.

4. Aprocess for refining sulfur-containing mineral oils containing organic disulfides, comprising reducing the disulfides by extraction of the sulfur bodies and other impurities from the mineral oil with substantially anhydrous liquid ammonia containing a reducing agent at a temperature and pressure at which both materials" are in the liquid phase, allowing the oily mixture to separate into two phases and removing the essentially liquid ammonia phase predominantly composed of ammonia from the ofl phase. 5. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising converting said disulfides to mercaptans with a reducing agent and extracting the sulfur bodies and other impurities from the resulting oil miirture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase in the presence of a cyanide soluble in liquid ammonia to d ssolve the sulfur bodies.

' 8. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising reducing the disulfides to mercaptans with a reducing agent, extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase in the presence of a cyanide soluble in liquid ammonia, and effecting the separation of the resulting essential liquid ammonia phase from the oil phase.

i 7. A process for refining sulfur-containing mineral oils containing organic disulfides, oom- I50 prising reducing the disulfides with a sulfo-reducing body, extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase in the presence of a cyanide soluble in liquid ammonia, and effecting the separation of the resulting essentially liquid ammonia phase predominantly composed of ammonia from the oil phase.

8. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising reducing the disulfides with a sulfo-re ducing body while extracting the sulfur bodies and other impurities from the mineral oil with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase in the presence of a cyanide soluble in liquid ammonia, allowing the oily mixture to separate into two phases, and removing the essentially liquid ammonia phase predominantly composed of ammonia from the oil phase.

9. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising reducing the disulfides by extraction of the sulfur bodies and other impurities from the' mineral oil with substantially anhydrous liquid ammonia containing a sulfo-reducing body at a tem'perature'and pressure at which both materials are in-the liquid phase, in the presence of a cyanide soluble in liquid ammonia, allowing the oily mixture to separate into two phases, and removing the essentially liquid ammonia phase predominantly composedof ammonia from the oil phase.

10. A process for refining sulfur-containing mineral oils comprising treating said mineral oil with a cyanide soluble in liquid ammonia and agitating the reaction mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase to dissolve the sulfur bodies.

11. A process for refining',sulfur-containing mineral oils comprising treating the mineral oil I with substantially anhydrous liquid ammonia at a temperature and pressure at which both mate-. rials are in the liquid phase in the presence of a cyanide soluble in liquid ammonia and effecting the separation of the resulting essentially liquid ammonia phase from the oil phase.

12. A process for .refining sulfur-containing mineral oils comprising agitating the mineral oil with substantially anhydrous liquid ammonia containing a cyanide soluble in liquid ammonia at a temperature and pressure at which the mineral oil and liquid ammonia are both in the tic liquid phase and effecting the separation of the resulting essentially liquid ammonia phase from the oil phase.

13. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising reducing the disulfides to mercaptans with a reducing agent, extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase in the presence of a modifying agent soluble in liquid ammonia and inert with respect to the ammonia, and possessing a non-neutral character therein, which agent modifies the sulfur bodies so as to make them more amenable to solution in the ammonia, and effecting the separation of the resulting essentially liquid ammonia phase from the oil phase.

15. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising reducing the disulfides with a sulfo-reducing body, extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase, in the presence of a modifying agent soluble in liquid ammonia and inert with respect to the ammonia, and possessing a non-neutral character therein, which agent modifies the sulfur bodies so as to make them more amenable to solution in the ammonia, and effecting the separation of the resulting essentially liquid ammonia phase predominantly composed of ammonia from the oil phase.

16. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising converting said disulfides to mercaptans with a reducing agent, and extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase in the presence of an inorganic amide soluble in liquid ammonia.

1'7. A process for refining sulfur-containing mineral oils containing. organic disulfides, comprising reducing the disulfldes to mercaptans with a reducing agent, extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase in the presence of an inorganic amide soluble in liquid ammonia, allowing the oily mixture to separate into two liquid phases, and efiecting the separation of the result:- ing essentially liquid ammonia phase predominantly composed of ammonia from the oil phase.

18. A process for refining sulfur-containing mineral oils containing organic disulfides, comprising reducing the disulfides with a sulfo-reducing body, extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase in the presence of an inorganic amide soluble in liquid ammonia, allowing the oily mixture to separate into two liquid phases, and effecting the separation of the resulting essentially liquid ammonia phase predominantly composed of ammonia from the oil phase.

19. A- process for refining sulfur-containing mineral oils containing organic disulfides, comprising converting said disulfldes to mercaptans with a reducing agent, and extracting the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pressure at which both materials are in the liquid phase in the presence of an ammonium salt'soluble in liquid ammonia but not having oxidizing properties.

' nia at a temperature and pressure at which both materials are in the liquid phase in the presence of an ammonium salt soluble in liquid ammonia, but not having oxidizing properties, and eiiecting the separation of the resulting essentially liquid ammonia phase predominantly composed of ammonia from the oil phase.

21. A process for refining sulfur-containing mineral oils containing organic disulii des, comprising reducing the disulfldes with a suli'o-reducin: body, extractinz'the sulfur bodies and other impurities from the resulting oil mixture with substantially anhydrous liquid ammonia at a temperature and pmsure at which both materials areintheliquidphase,inthepresenceoianam. monium salt soluble in liquid ammonia but not having oxidizing properties and eiiecting the separation o! the resulting essentially liquid ammonia phase predominantly composed of ammcnia from the oil phase. I

' LUDWIG 

